$nested_array = [ 1, 2, [3, 4], ]; $iterator = new RecursiveIteratorIterator( new RecursiveArrayIterator($nested_array), RecursiveIteratorIterator::SELF_FIRST ); foreach ($iterator as $item) { echo $iterator->current() . PHP_EOL; }
class CustomFilterIterator extends FilterIterator { public function accept() { return strpos($this->getInnerIterator()->current(), 'a') !== false; } } $data = ['apple', 'banana', 'carrot']; $iterator = new RecursiveIteratorIterator(new CustomFilterIterator(new ArrayIterator($data))); foreach ($iterator as $item) { echo $iterator->current() . PHP_EOL; }This code example uses the `RecursiveIteratorIterator::current()` function to print the current element of a recursive iterator. The recursive iterator is created using the `CustomFilterIterator` class. The `CustomFilterIterator` class implements the `FilterIterator` interface and filters out all elements that do not contain the letter 'a'. Package Library: Standard PHP Library (SPL)